Hi everyone, this is the update on the final phase of my progress in enhancing Nominatim’s search results ranking.

Previous Diary Entries

To have a background understanding of the project, you can check the overview of the project followed by the project’s first phase down below.

1. Project Overview
2. Phase 1

Project’s Pull Request

To see the code of the project, you can check the pull request here.

Detailed Report of the Project

The detailed version of the report can be read here.

What Has Been Done

• Enabled PostGIS to work with raster files
• Nominatim CLI tool can now import OSM views data from the GeoTIFF file
• Nominatim CLI tool has the ability to refresh the OSM views data and recompute the importance scores
• Integrated OSM views data into the algorithm that computes the places’ importance scores which are used in ranking Nominatim’s search results
• Added some unit tests
• Updated the documentation and added a detailed report of the experiments conducted

Possible Next Steps

There is a weak correlation between the OSM views data and the wiki importance data. A number of possible reasons have been outlined in the detailed version of this report in which further investigation is needed to have a better understanding of this outcome. Apart from that, the OSM views import feature can be enhanced so that the user can specify the zoom level when importing the data, or even have multiple zoom levels data imported one after the other so that the OSM views data have a higher degree of accuracy.

What I have learned

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Hi everyone, this is an update on my progress in enhancing Nominatim’s search results ranking. For an overview of the project, you can check out my previous diary entry here. I would like to thank my mentors, Sarah Hoffman (@lonvia) and Marc Tobias (@mtmail), for their guidance throughout the implementation of this project.

Goals of the First Phase

The first phase of this project has some goals which were previously set. Below are the main goals of this phase.

• Enabling PostGIS to work with raster files
• Finding and implementing the most suitable method used to import GeoTIFF files
• Conducting performance tests on the import functionality
• Adding unit tests
• Documenting the new changes

Hardware I Am Using

Since Nominatim with a full planet import needs a lot of computing resources, I had set up the server which allowed me to work on the project. I would like to thank OpenCage for providing me with the server to work with on this project. The specifications of the server that I am currently using are 8 core AMD Ryzen™ 7 3700X, 64GB RAM, 1TB NVMe disk (900GB usable, 850GB free), running Ubuntu 22.04 LTS.

OSM Views Data

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Hi everyone, my name is Tareq Al-Ahdal. I am a computer science undergraduate student at Universiti Teknologi Malaysia. Recently, I got accepted into Google Summer of Code 2022 as an open source contributor with OpenStreetMap. I will work this summer on enhancing Nominatim: OpenStreetMap’s geocoding software that enables us to search and find location addresses based on their names and vice versa.

Nominatim is currently using a computed importance value to rank the search results based on the location’s perceived importance. This importance value is derived from the popularity of the Wikipedia article of each location. However, not every location on earth has its own Wikipedia article. As a result, the locations that do not have their own Wikipedia articles will not have an importance value, thereby the ranking of the search results, in that case, is deemed inaccurate. OpenStreetMap has data regarding the number of times users accessed each location on the map. This data is a good indicator of how popular a place is. The aim of my work is to integrate this data into Nominam’s computation of the importance value so that the search results become more accurate which will help the users find the correct places that they are looking for in less time.

I will use this diary to keep you updated about my work. Please feel free to reach out if you have any questions regarding my work or anything else you have in mind.